Attempts have been made to provide portable coffee brewing devices that may be operated without a power source. These portable devices may be referred to as French presses. The French press comprises a container and a filter plate joined to a shaft. Coffee grounds and water are inserted into the container and mixed together. The filter plate is then inserted into the container and the shaft connected to the filter plate is pushed down so that the filter plate travels down in the container. The filter is arranged so that as it travels down in the container, liquid coffee passes up through the filter plate while the grounds are trapped on or adjacent to the bottom face of the filter plate. Eventually, the liquid coffee in the container is separated from the solid grounds by the filter plate. The container may then be opened and the liquid coffee poured out or consumed directly.
There are several undesirable limitations associated with the use of a French press for making brewed coffee. First, it is difficult to effectively separate the grounds from the liquid coffee. The filter pores must be big enough to allow the liquid coffee to pass therethrough using a reasonable amount of manual pressure to isolate the grounds from the liquid. As a result, small coffee particles also pass through the filter pores and the brewed coffee contains an undesirable quantity of coffee grounds. Second, the brewing process can be lengthy because it takes considerable time to adequately mix the coffee grounds with the water and press the brewed coffee. Thus, the hot water used to make the brewed coffee may cool in the time it takes to brew the coffee.
There is a need for a portable brewing device that effectively separates the solids from the brewed liquid, brews the liquid in a short period of time, and is relatively easy to use, self contained and easy to transport.